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https://issues.apache.org/jira/browse/SPARK-19347?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Marcelo Vanzin resolved SPARK-19347.
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Resolution: Fixed
Assignee: jin xing
Fix Version/s: 2.2.0
> ReceiverSupervisorImpl can add block to ReceiverTracker multiple times
> because of askWithRetry
> ----------------------------------------------------------------------------------------------
>
> Key: SPARK-19347
> URL: https://issues.apache.org/jira/browse/SPARK-19347
> Project: Spark
> Issue Type: Bug
> Components: DStreams, Spark Core
> Reporter: jin xing
> Assignee: jin xing
> Fix For: 2.2.0
>
>
> *ReceiverSupervisorImpl* on executor side reports block's meta back to
> *ReceiverTracker* on driver side. In current code, *askWithRetry* is used.
> However, for *AddBlock*, *ReceiverTracker* is not idempotent, which may
> result in messages are processed multiple times.
> To reproduce:
> 1. Check if it is the first time receiving *AddBlock* in *ReceiverTracker*,
> if so sleep long enough(say 200 seconds), thus the first RPC call will be
> timeout in *askWithRetry*, then *AddBlock* will be resent.
> 2. Rebuild Spark and run following job:
> {code}
> def streamProcessing(): Unit = {
> val conf = new SparkConf()
> .setAppName("StreamingTest")
> .setMaster(masterUrl)
> val ssc = new StreamingContext(conf, Seconds(200))
> val stream = ssc.socketTextStream("localhost", 1234)
> stream.print()
> ssc.start()
> ssc.awaitTermination()
> }
> {code}
> To fix:
> It makes sense to provide a blocking version *ask* in *RpcEndpointRef*, as
> [~vanzin] mentioned in SPARK-18113
> (https://github.com/apache/spark/pull/16503#event-927953218), *askWithRetry*
> is a leftover from akka days. It imposes restrictions on the caller(e.g.
> idempotency) and other things that people generally don't pay that much
> attention to when using it.
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